US Patent 7037059 Self-tapping screw for composite materials

In accordance with an embodiment of the invention the threads of the two thread sections have an opposite pitch. Further, chips are reduced in that the tip of the screw near the thread section has been configured as a multiple screw-thread, in particular a double screw-thread, where the pitch of the threads of the multiple screw-thread is greater than the pitch of the single screw-thread of the thread section near the head of the screw.